Field of the Invention
The invention relates to a motor controller and a fan system comprising the same.
Description of the Related Art
A typical motor controller includes a control box and a control circuit board. The control box is provided with a cavity, and the control circuit board is disposed in the cavity of the control box. The motor controller is generally disposed at a bottom part of a load box. Limited by the space, the motor controller generally has a small volume, thereby resulting in poor heat dissipation performance; besides, heat quantity produced by the motor is accumulated at the bottom part of the load box. Because the control circuit board is mounted inside the sealed control box, when the temperature therein increases and the heat quantity in the control box is difficult to dissipate, the normal operation of the control circuit board will be seriously affected. Thus, the motor controller of such structure has low reliability and hidden dangers. Some manufacturers have adopted methods of arranging cooling ribs or vent holes on an outer surface of the control box to improve the heat dissipation performance of the motor controller, but such motor controller is troublesome in assembly and the heat dissipation effect thereof is not ideal.
A typical fan system includes a volute, a wind wheel, a motor, and a motor controller. The volute is provided with an inner cavity. An end face of the volute is provided with an air inlet, and a side face of the volute is provided with an air outlet. The motor is disposed outside the air inlet of the volute; a rotating shaft of the motor is inserted into the inner cavity from the air inlet and connected to the wind wheel; and the motor controller is generally disposed away of the motor. Since the motor is far away from the motor controller, a lead wire demanded for connection is so long that a large space is occupied; furthermore, it is troublesome to connect the long lead wire, faults easily occur, and hidden dangers exist. In some existing motors, the motor controller is disposed near the motor. However, since the motor controller is a sealed structure, poor dissipation performance of the motor controller is resulted. After a long term operation of the motor controller, the temperature inside the motor controller increases, so that the normal operation of the motor controller is affected, and faults easily occur during the operation of the motor under the control of the motor, thereby resulting in low reliability.